The basic configuration of a conventional viscous material application apparatus is described with reference to the schematic illustrations of FIG. 29A and FIG. 29B. As shown in FIG. 29A, this viscous material application apparatus comprises a material supply section 1 for holding a viscous material 5 such as an adhesive or cream solder, and a pressure regulating section 22 for regulating and supplying compressed air to the material supply section 1, and the viscous material 5 is pressurized by the compressed air, and discharged from a discharge port 4a of a discharge section 4.
Furthermore as shown in FIG. 29B, in some cases a valve 16 for starting and stopping the supply of compressed air may also be provided between the material supply section 1 and the discharge section 4. In this apparatus, in the case where a predetermined quantity of the viscous material 5 is required to be discharged, the viscous material 5 is pressurized from above by compressed air supplied from the pressure regulating section 22 and forced downward, and the valve 16 is then opened and the viscous material 5 discharged from the discharge port 4a. Then, when application onto the circuit board has been completed, the valve 16 is closed.
However, in a viscous material application apparatus of the conventional configuration described above, because the compressed air supplied from the pressure regulating section 22 is applied on top of the viscous material 5 contained in the material supply section 1, then depending on the characteristics of the viscous material 5, the pressure of the compressed air may be affected by the viscosity resistance of the viscous material 5 and find it difficult to reach the vicinity of the distant discharge port 4a of the discharge section 4. Consequently, variations developed in the pressure transmission, and it was difficult to obtain highly accurate discharge quantities and discharge pressures.
Furthermore as shown in FIG. 30, the response time from the point where a signal is output to start discharge at a predetermined pressure, to the point where discharge at that pressure is actually started, also lengthens for the same reasons, and so a waiting period develops from transmission of a discharge start signal to the actual start of discharge. In addition, after stopping pressurization residual pressure remains, and so other problems arise such as the viscous material 5 hanging down from the discharge port 4a being forced out near the discharge port 4a and adhering to the circuit board, creating a bridge, when the viscous material application apparatus is next positioned on the circuit board.
Furthermore in the aforementioned conventional apparatus, in those cases where a device called a multiple nozzle 4c with a plurality of discharge ports 4d, such as that shown in FIG. 31A and FIG. 31B, was used for performing a two dimensional bulk supply of the viscous material, the following problems also arose. In highly viscous materials, the pressure transmission through to the viscous material 5 does not occur uniformly, and when a conductive paste 31 was applied to a circuit board 32, then as shown in FIG. 32A and FIG. 32B, because the transmitted pressure from the compressed air differed depending on the position of the discharge port 4d, a variation developed in the discharge quantity depending on the discharge position.
The present invention aims to resolve the above problems, with an object of providing a viscous material application apparatus capable of improving discharge accuracy and increasing efficiency by carrying out the pressure transmission for discharging the viscous material efficiently, and improving the responsiveness.